The present invention relates to a method for extinguishing or "killing" fires of classes A, B, and C in enclosed spaces such as engine compartments and crew compartments of combat military vehicles. In the past, the most effective agents for fire killing have been Halons, and CFC and HFC type chemical gasses. Though effective against fires, these agents have adverse environmental effects and can be highly toxic. The present invention addresses the foregoing concerns by using water-based, relatively inert salts that do not have the toxicity or harmful environmental effects of Halons, CFC, or HFC gasses.
Presently, the most effective nontoxic fire extinguishing agents kill fires through a complex phenomenon that involves both cooling and chemically acting on reagents of the fire. The chemical aspect of the phenomenon is known as "free radical scavenging" or as a "free radical trap". Our scheme utilizes a halide salt or acetate salt dissolved in water that likewise both cools and chemically reacts to kill fires. Our extinguishant includes a nontoxic, nonflammable freezing point suppressant which makes the extinguishant useful in arctic climates. The extinguishant is also usable under extremely hot climatic conditions of deserts or tropical areas.
Our extinguishant has a surfactant to reduce the extinguishant's droplet size when the extinguishant is sprayed. In our overall fire extinguishing scheme, the extinguishant's chemical reactions occur only in the presence of heat from an incident fire, whereby these reactions do not unintentionally occur during accidental discharge of the extinguishant. Consequently, our fire extinguishing scheme is safer than many known fire fighting methods.
In some instances in our use of the extinguishant, it may flow in a line past a small phial or container whose mouth opens to the line. Across the mouth is a screen coated on one side with polytetrafluorethylene (TEFLON.RTM.), the screen retaining water in the phial unless extinguishant in the line flows past the screen. Water from the phial replaces water that may be vaporized downstream of the phial. The screen prevents deposits of the extinguishant from forming in the line and clogging the line. Articles such as boats and coffee cups have previously been made, at least for demonstration purposes, from the same material as the aforementioned screen, but we believe it is not known to use such a screen as we have.